#!/usr/bin/env bash

shopt -s nullglob

usage() {
    echo "Usage: $(basename "$0") [ -x <exclude> ]*"
    exit 1
}

remove_empty_directories() {
    find . -depth -type d |
        sed 's|^\./||' |
        grep -Ev '^\.$|^\.git/|^\.git$' |
        while read -r d; do
	    for f in "$d"/{*,.*}; do
		if ! [ -e "$f" ]; then
		    rmdir "$d"
		fi
		break
	    done
	done
}

git_options=(-e TAGS)

while [ "${1#-}" != "$1" ]; do
    case "$1" in
	-x)
	    git_options+=(-e "$2")
	    shift; shift;;
	*)
	    usage;;
    esac
done

for d in "${@-.}"; do
  (
    if cd "$d"; then
      if [ -e .git ] || [ -e ../.git ]; then
        if ! type -p git >&/dev/null; then
          echo "$0: git: not found."
          exit 0
        fi
        git clean -f -d -x "${git_options[@]}" >/dev/null
        remove_empty_directories
      else
        echo "$0: $d: not administered by Git."
      fi
    fi
  )
done